Conveyed-Adherent: Referring to the method of automated fabrication described herein, in which successive patterns of fabrication material are formed on a substrate, and then the patterns of fabrication material are conveyed on the substrate into successive positions, and then the substrate is removed from the fabrication material. Conveyed-Adherent autofab may be implemented in either a fully additive or in a hybrid fashion. xe2x80x9cConveyed-Adherentxe2x80x9d is a trademark of Ennex Fabrication Technologies of Los Angeles.
Carried-Sheet: Referring to a hybrid implementation of Conveyed-Adherent autofab in which the fabrication material is supplied in sheet form, and in which the patterns of fabrication material are determined by cutting the shapes of the patterns into successive pieces of the sheet material. xe2x80x9cCarried-Sheetxe2x80x9d is a trademark of Ennex Fabrication Technologies of Los Angeles.
Fabrication medium: Sheet material moving through a Conveyed-Adherent fabricator, consisting of adjacent substrate and fabrication material. The material moving through a fabricator may be sliced into individual segments of fabrication medium, or it may be a long, continuous fabrication medium containing the fabrication material for many successive layers.
Positive region: The region of space which is or will be occupied by a fabricated object or by material which will form part of a fabricated object.
Positive material: Fabrication material which does or will occupy a positive region and therefore does or will compose a fabricated object or part of a fabricated object.
Negative region: The region of space complimentary to a positive region.
Negative material: Fabrication material which does or will occupy a negative region and will therefore be removed.
Weeding: Separation of negative material from positive material in a single layer of fabrication material in a Carried-Sheet fabricator, so called because it is the removal of unwanted material.
Lay-down: Establishment of contact of fabrication material with stack.
Peel-off: Incremental removal (peeling) of substrate from fabrication material.
Consequent peel-off: Stacking in which lay-down is completed before peel-off begins.
Concurrent peel-off: Stacking in which peel-off is begun while lay-down is still in progress.
Simultaneous peel-off: Concurrent peel-off in which peel-off at each point is approximately simultaneous with lay-down at that point.
Delayed peel-off: Concurrent peel-off in which peel-off at each point takes point with some delay after lay-down at that point.
Platen: In a stacker, device that imparts forces on a fabrication medium to enact lay-down and/or peel-off.
Face of a platen: Portion of the surface of the platen which contacts a fabrication medium.
Shape of a platen: Shape of the platen""s face.
Holding device or holding system: In a stacker, device or system which controls the motion and tension of the fabrication medium during lay-down and peel-off.
Holding platen: Combination of a platen to which the fabrication medium is rigidly held and the portion of the holding system which so holds the fabrication medium.
Flat: Description of a smooth surface at a point through which two different straight lines can be drawn in the surface.
Singly curved (having single curvature): Description of a smooth surface at a point through which only one straight line can be drawn in the surface.
Axis of curvature at a point of a singly curved surface: The one straight line which can be drawn in the surface through that point.
Doubly curved (having double curvature): Description of a smooth surface at a point through which no straight line can be drawn.
Radius of action: In a lay-down or peel-off action being performed by any kind of complicated platen system, the radius of a roller that would provide approximately the same configuration of forces as are actually being applied.
1. Field of the Invention
This invention relates to a method and apparatus for automatic fabrication of three-dimensional objects from a plurality of individual layers of fabrication material stacked together in sequence to form the object. More particularly, the invention relates to the use of a substrate to convey each layer to a station where these layers are affixed to each other and then the substrate is removed.
2. Background Discussion
The idea of automated fabrication of three-dimensional solid objects dates back at least to the 18th century, when a pantograph-like device was used in France to copy medallions. James Watt later built several machines, based on the same principal, capable of carving full human busts. Over the past 45 years, machining, lathe-turning and grinding devices have been placed under computer control (called xe2x80x9cCNCxe2x80x9d for xe2x80x9ccomputer-numerical controlxe2x80x9d) to allow the generation of original shapes from designs entered into computers by engineers using computer-aided design (CAD) software. These processes are called xe2x80x9csubtractivexe2x80x9d fabrication, because they start with a solid block of material and generate the desired shape by removing material from the block.
Since the subtractive processes work by applying a cutting tool to a solid block, they have the common disadvantage of being limited in the shapes that they can generate. Intricate or nested structures are difficult or impossible to build by these methods. A more modern approach is xe2x80x9cadditivexe2x80x9d fabrication in which a fluid or powdered material is solidified or congealed in successive small regions or layers to form the desired object. This idea goes back at least to the photo-relief process of Baese (U.S. Pat. No. 774,549), and has been substantially refined through dual-laser photopolymerization of Swainson (Danish Patent Application 3611), liquid droplet deposition of Masters (U.S. Pat. No. 4,665,492), single-laser photopolymerization of Andre (French Patent Application 84 11241) and Hull (U.S. Pat. No. 4,575,330), masked-lamp photopolymerization of Pomerantz (U.S. Pat. No. 4,961,154) and Fudim (U.S. Pat. No. 5,135,379), laser sintering of Feygin (U.S. Pat. No. 4,752,352) and Deckard (U.S. Pat. No. 4,863,538), and robotically guided extrusion of Crump (U.S. Pat. No. 5,121,329).
There are also several hybrid processes which combine additive and subtractive processes. Usually this involves cutting or etching the contours of individual layers of an object, and stacking and binding the contours. The earliest use of such a process is that of Morioka (U.S. Pat. No. 2,015,457), and more recent refinements have been made by DiMatteo (U.S. Pat. No. 3,932,923), Feygin (U.S. Pat. No. 4,752,352), Kinzie (U.S. Pat. No. 5,015,312), and Berman (U.S. Pat. No. 5,071,503).
Sparx AB of Sweden and Schroff Development Corporation of Mission, Kans., have manufactured manual systems which use a substrate to carry a sheet of fabrication material bonded to a substrate. Individual layers of material are formed by cutting through the material, removing negative material, and, prior to affixing successive layers, removing the substrate. These systems are similar to a Carried-Sheet fabricator, except that their operation is not fully automated and therefore cannot achieve the accuracy, speed, and ease of use of a Carried-Sheet fabricator.
All of the prior additive and hybrid processes suffer from several or all of the following drawbacks:
(1) Accuracy and resolution are limited to the domain of about 0.1 millimeters (0.004 inch). One reason is the difficulty of controlling the action of a laser beam (whether for irradiating, as in Hull or Deckard, or for cutting, as in Feygin), a particle jet (as in Masters), or an extrusion head (as in Crump), plus the difficulty of compensating for the width of the laser beam, jet stream or extrusion bead. Another reason is the minimum thickness of a single layer that can be formed from the raw material liquid or powder, or the minimum thickness of the extrusion bead that can be laid down.
(2) In the fully additive processes, large regions of solid material take a long time to fabricate, slowing down the process for building structures with such large solid regions.
(3) All of the processes are difficult and expensive to scale up for fabrication of large objects, because they involve complicated mechanisms of laser optics or robotics.
(4) All of the processes call for fabrication specifically in very thin layers, which limits the fabricator speed unnecessarily in cases where great resolution in the vertical direction is not necessary. In many instances, fabricator users would like to get a fast, low resolution, rendition of the desired object, but none of the prior art provides a way to achieve this.
(5) Only Kinzie and Crump provide a way to achieve a mixture of colors in the object generated. Kinzie requires a secondary printing process on special absorbent or translucent material to achieve this, and Crump requires the use of specially died materials.
(6) All of the processes always produce a solid object in a permanently fixed configuration, such that any fracturing or cross-sectioning of the object is tantamount to destroying it. No means has ever been provided for generating an object which can be temporarily taken apart into sections and easily reassembled with no loss of integrity.
(7) The raw materials for most of the processes are specialty chemicals which are expensive and, in some cases, are toxic or require special handling to prevent combustion.
(8) Many of the processes are limited to working with certain types of materials such as only photopolymers in the simple photocuring methods, or only thermally softenable materials in laser sintering.
(9) Most of the processes hide the object being built in an opaque solid or a murky liquid environment, depriving the fabricator user from the pleasure and benefit of watching the object take shape.
(10) All of the processes, except that of Sparx AB, use complicated and expensive mechanisms and/or electro-optical devices, making fabricators based on them large, heavy, expensive and difficult to maintain.
The ultimate commercial importance of automatic fabrication of three-dimensional objects is hampered by these disadvantages.
The method and apparatus of this invention has several features, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this invention as expressed by the claims which follow, its more prominent features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled, xe2x80x9cDETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTSxe2x80x9d one will understand how the features of this invention provide its advantages, which include:
(1) Accuracy and resolution can both be easily achieved in the domain of about 0.05 millimeters (0.002 inch). This can be further reduced to less than about 0.01 millimeters (0.0004 inch) with specially accurate cutting or positioning mechanisms and very thin materials.
(2) In several embodiments of this invention in which layers of the desired object are cut from sheet material, large regions of solid material are fabricated very quickly because they only require cutting around the periphery.
(3) In embodiments of this invention in which layers of the desired object are cut from sheet material, it is easy to scale up to build large objects. This is because the required mechanisms and components are quite simple and, in many cases, are already available for other purposes in large size formats.
(4) Thicker layers of materials are used when vertical resolution can be sacrificed for speed. This option is analogous to the xe2x80x9cdraft modexe2x80x9d available on dot matrix printers to achieve fast, low resolution, output. A means (angular cutting) is also provided for ameliorating this reduction of resolution.
(5) Colors can be easily incorporated and mixed in any desired degree of complexity in the fabricated object. For several embodiments, in which layers of the desired object are cut from sheet material, at least 60 colors are already available.
(6) In one variation of the method of this invention, fabricated objects are not permanently fixed, but can be easily separated at any one or more of many cross sections. The resulting sections can then be easily rejoined to form again the complete object. The object can be thus separated and rejoined at the same or different cross sections, repeatedly and without limitation.
(7) For several embodiments of this invention in which layers of the desired object are cut from sheet material, the raw materials are readily available and include inexpensive varieties. The materials are nontoxic and have no special handling or storage requirements.
(8) A wide variety of materials may be used in the process, including, metals, plastics, ceramics, and composites.
(9) The method of this invention can be practiced so as to leave the object being built visible during the fabrication process, providing the user with the pleasure and benefit of watching the object take shape.
(10) The method can be embodied using simple and inexpensive mechanisms, so that the fabricator equipment can be relatively small, light, inexpensive and easy to maintain.
The invention includes several methods for fabricating a three-dimensional object.
In the first method the fabrication material is formed into individual layers on a carrier substrate. Each layer has a predetermined configuration, and successive layers are stacked in a predetermined sequence and affixed together to form the object. The layers may vary in curvature, thickness, color, outline, and material composition from layer to layer or even within an individual layer.
In one embodiment, the method includes the steps of
(a) providing a stacker, which is a station were the successive layers are stacked together,
(b) forming on a carrier substrate a first layer of fabrication material,
(c) conveying the first layer of fabrication material on said carrier substrate to said stacker and transferring to a base in said stacker,
(d) separating the carrier substrate from the fabrication material, exposing a bonding surface on said first layer to which successive layers may be affixed,
(e) forming on the carrier substrate a second layer of fabrication material and conveying the second layer of fabrication material on the carrier substrate to the stacker,
(f) aligning the second layer in correct position with respect to said first layer and bringing the second layer into contact with the bonding surface on the first layer so that said layers become affixed together in the correct relative position and begin to form a stack,
(g) separating by peeling said carrier substrate from the fabrication material after affixing the second layer to the first layer, exposing a bonding surface on the second layer to which other successive fabrication layers may be affixed, and
(h) repeatedly forming and conveying successive fabrication layers on the carrier substrate in series to the stacker and aligning in correct position and then affixing the successive fabrication layers to the stack thus being formed and then separating the carrier substrate from each successive fabrication layer, until said object is formed as said stack.
This first method of this invention can be implemented either in an additive embodiment or in a hybrid embodiment where material is both added and subtracted. In the additive embodiment, the method calls for depositing on the carrier substrate successive layers of fabrication material having a configuration with predetermined boundaries where substantially no material is deposited outside the boundaries.
In the hybrid embodiment, the method calls for dividing the layers of fabrication material into a negative region of waste material and a positive region corresponding to the configuration of an individual fabrication layer, and then separating the negative material from the positive. The fabrication material may be in the form of a sheet of fabrication material supported by the carrier substrate, and the positive and negative regions may be formed by cutting through the material but not cutting through the substrate. The negative material may be left in place on the substrate when this layer is conveyed to the stacker, and removed along with the substrate when the substrate is separated from the positive material bonded to the stack. In either an additive or a hybrid embodiment, an adhesive may be used as a component of the fabrication material and/or of the substrate. Such adhesive component may participate in the bonding of layers to the stack, and/or it may hold the fabrication material to the substrate but allowing the substrate to be separated from the fabrication material when the positive material of the layer has become affixed to the stack.
In the second method the fabrication material is formed into individual layers, where successive individual layers are stacked to form said object. This method includes
(a) providing a station where the successive individual layers are formed into a stack,
(b) placing on a carrier substrate a first layer of fabrication material corresponding to the configuration of one individual layer,
(c) conveying the first layer of fabrication material on said carrier substrate to said station,
(d) prior to separating the carrier substrate selectively inducing bonding of at least a portion of the fabrication material to the stack, and
(d) separating said carrier substrate after bonding said one individual layer to said stack.
The third method includes
(a) providing a station where the successive individual layers are stacked together to form a stack,
(b) placing on a carrier substrate a first layer of fabrication material and dividing said first layer of fabrication material into a negative region of waste material and a positive region corresponding to the configuration of one individual layer,
(c) conveying the divided, first layer of fabrication material on said carrier substrate to said station,
(d) prior to separating the carrier substrate, including the negative region of waste material, from the positive region, selectively inducing bonding of at least a portion of the positive region to the stack, and
(d) separating said carrier substrate, including the negative region of waste material, from the positive region after bonding said positive region to said stack.
The fourth method includes
(a) providing a station where the successive individual layers are stacked together,
(b) placing on a carrier substrate a first layer of fabrication material and dividing said first layer of fabrication material into a negative region of waste material and a positive region corresponding to the configuration of one individual layer,
(c) conveying the divided, first layer of fabrication material on said carrier substrate to said station and transferring to said station,
(d) separating the carrier substrate, including the negative region of waste material, from the positive region, exposing a bonding surface on said one individual layer to which a successive individual layer is affixed, said bonding surface including a first region which accepts a second layer of fabrication material and a second region that interferes with attaching said second layer of fabrication material to the bonding surface,
(e) deactivating the second region of the bonding surface prior to affixing said second layer of fabrication material to the bonding surface,
(f) placing on the carrier substrate a second layer of fabrication material and dividing said second layer of fabrication material into another negative region of waste material and another positive region corresponding to the configuration of a successive individual layer, and conveying the divided, second layer of fabrication material on the carrier substrate to said station,
(g) aligning said individual layers and bringing said bonding surface on said one individual layer into contact with said successive individual layer so that said layers become affixed together,
(h) separating said carrier substrate, including the negative region of waste material, from the positive region after affixing said one individual layer to said successive layer, exposing a bonding surface on said successive individual layer to which another successive fabrication layer is affixed, and
(i) repeatedly aligning and then affixing successive fabrication layers together divided into positive and negative regions after conveying said successive fabrication layers on the carrier substrate in series to the station until said object is formed, first affixing individual successive fabrication layers together and then separating the carrier substrate, including the negative region of waste material, from each individual, successive fabrication layer.
The fifth method calls for an improved way of fabricating a three-dimensional object from fabrication material formed into individual layers having a predetermined configuration, where successive individual layers are stacked in a predetermined sequence and affixed together to form said object. In this improved method a station is provided where the successive individual layers are stacked together, the successive layers being conveyed to the stacking station on a carrier substrate after dividing individual successive layers into a negative region of waste material and a positive region corresponding to the configuration of one individual layer, and separating the carrier substrate, along with the negative region of waste material, from the positive region, exposing a bonding surface on said one individual layer to which successive individual layers may be affixed. The improvement comprises selectively deactivating at least a portion of the bonding surface.
A sixth method includes
(a) providing a station where the successive individual layers are aligned and affixed together to form a stack having a bonding surface to which a successive individual layer is affixed,
(b) placing one successive layer of fabrication material on a carrier substrate carried on a platen positioned next to said station, and
(c) bringing said platen into engagement with the stack to affix the one successive layer to the bonding surface, and
(d) separating said carrier substrate from the one successive layer when said one successive layer is affixed to the bonding surface by moving the platen to pull incrementally the carrier substrate from the stack.
In this sixth method substantially all of the fabrication material in each layer is affixed to the stack prior to removing the carrier substrate. A portion of the fabrication material in one layer is affixed to the stack, but before all the fabrication material in said one layer is affixed, a portion of the carrier substrate is removed. The fabrication material is affixed to the stack at the same time the carrier substrate is being removed. In this sixth method the platen has a face with (a) a constant single curvature, (b) a flexible curvature, or (c) a controlled curvature. The carrier substrate is releasably held to the platen, with the layer of fabrication material on the carrier substrate placed on the platen uniformly to avoid entrapment of air between the carrier substrate and the platen, so that the layer of fabrication material does not wrinkle or buckle.
A seventh method for fabricating a three-dimensional object comprises automatically forming a stack of layers corresponding to the object by stacking said layers in a predetermined sequence. The individual layers each are first formed into a predetermined two-dimensional configuration as required to form the object, with at least some of the layers having a non-flat shape. Preferably, there is a base supporting the layers. This base has a curved surface, and at least one of the layers is placed on the curved surface of the base, so that the one layer has a non-flat shape conforming to the curved surface of the base. The base element may be placed at the bottom of the stack or between layers. In this seventh method, from layer to layer the size of the layers are different to create a curvature as subsequent layers are overlaid.
An eighth method comprises stacking a plurality of layers together in a predetermined sequence and affixing them together to form the object, at least some of the layers being formed from a pliable material having thicknesses which vary as mathematical functions of the surface extent of the layers, where said mathematical functions are calculated to accommodate the curvature said individual layers will assume in the stack, such curvature causing the thickness of the layer to change when stacked. The layers are conveyed to a stacking station on a carrier substrate, each layer preferably having the ability to adhere to a stack of previous layers. There may be an interstitial base element placed between layers of material or from layer to layer the size of the layers are different to create a curvature as subsequent layers are overlaid.
A ninth method includes
(a) providing a station were the successive individual layers are stacked together,
(b) forming on a surface of one or more carrier substrates a series of layers of fabrication material corresponding to the configuration of individual layers by extruding the fabrication material through a nozzle guided over said surface of a carrier substrate,
(c) conveying said layers of fabrication material on a carrier substrate to said station,
(d) aligning layers and bringing each of said individual layers into contact with a successive individual layer so that said layers become affixed, and
(e) separating the carrier substrate from the individual layers of fabrication material, exposing a bonding surface to which a successive individual layer is affixed.
A tenth method calls for individual layers to be stacked in a predetermined sequence and affixed together to form the object with minimal layer-to-layer graininess. This method includes
(a) forming said individual layers with edges that slope in a manner that minimizes layer-to-layer graininess upon stacking the successive layers on top of each other, said edges forming corners with the surfaces of the layers, and
(d) stacking said individual layers together in a predetermined manner with the corners of one edge meeting the corners of the edges of both the previous layer and the next following layer, whereby layer-to-layer graininess is minimized.
An eleventh method calls for at least two of layers being bonded by a process which is capable of being released and reactivated, so that the object may be separated into sections along an interface between said two layers and easily reassembled.
A twelfth method is draft mode. In this method, each of the layers has a predetermined thickness which is several times thicker than the thickness of the layers needed to attain normally acceptable resolution. These thicker layers reduce the layer-to-layer resolution of the object but enable the object to be fabricated at a substantially higher speed than that attainable at normally acceptable resolution. The thickness of the layers to attain normally acceptable resolution is from 0.01 to 25 millimeters, and each of the layers has a predetermined thickness at least 3 times the thickness to attain normally acceptable resolution.
In general, the apparatus includes a formation station where successive layers of fabrication material are formed on a carrier substrate and then conveyed to a stacker where they are separated from the substrate and bonded together to form the desired three-dimensional object. The following are some of its major features. Other features are discussed in the section xe2x80x9cDetailed Description Of The Preferred Embodiments.xe2x80x9d
The first feature of the apparatus of this invention is the formation station where the successive, individual fabrication layers are formed on successive carrier substrates. The layers of fabrication material each have a predetermined configuration, and successive layers are stacked in a predetermined sequence and affixed together to form the object at a stacker. The substrate and fabrication material may be in the form of a sheet and there may be an adhesive component of the fabrication material and/or of the substrate which participates in the bonding of the layers to the stack and/or holds the fabrication material to the substrate but allows the substrate to be separated from the fabrication material when the positive material of the layer has become affixed to the stack.
The second feature is that a deposition mechanism may be used to deposit on a carrier substrate a fabrication material to form successive layers, each successive layer having a configuration with predetermined boundaries, with substantially no material deposited outside said predetermined boundaries.
In an alternate embodiment, a fabrication material may be supplied in the form of a sheet on a substrate, and a cutter may be used to cut through the fabrication material, but not though the substrate, to divide the fabrication material into a negative region of waste material and a positive region corresponding to the configuration of an individual layer. In one embodiment, a waste material removing mechanism (xe2x80x9cweederxe2x80x9d) removes the negative material from a layer prior to conveying the layer to the stack. The negative material may alternatively remain on the substrate until after the layer is adhered to the stack, and when the substrate is separated the negative material adheres thereto and is thereby removed.
The third feature is a conveyor for conveying in the predetermined sequence the successive fabrication layers on the successive carrier substrates from the formation station to the stacker. An alignment mechanism aligns the successive fabrication layers so that each successive fabrication layer is in the correct position with respect to the stack.
The fourth feature is that successive carrier substrates may be sections of a continuous belt which travels along a predetermined path past the formation station and stacker. There are means for placing onto the belt in advance of the stacker fabrication material corresponding to the physical dimensions of an individual layer. If the fabrication material is cut into positive and negative regions, there are means for transferring the positive material to the stacker and for removing the negative material prior to placing onto the belt a successive layer of fabrication material. Instead of a continuous belt, the substrate may be a series of individual sheets, sections of a roll of material, or a single plate used repeatedly, or a revolving set of such plates.
The fifth feature is a separator which separates each successive carrier substrate from the fabrication layer thereon to expose a bonding surface on each fabrication layer. An affixing mechanism brings each successive fabrication layer conveyed to the stacker into contact with the stack, allowing or inducing the new layer and the stack to bond to each other.
The sixth feature is that the separator separates each successive carrier substrate from the fabrication layer thereon after affixation of this layer to the stack.
The seventh feature is a weeder mechanism which selectively removes the negative region of waste material from the carrier substrate. The weeder mechanism, which is in advance of the stacking station, may include a pick-up film which selectively contacts the negative region of waste material. The weeder mechanism may also include a device which selectively treats at least a portion of the negative region of waste material to render the selected portion susceptible to adhesion to the pick-up film which subsequently contacts the negative region of waste material. The weeder mechanism may include a barb element that selectively engages and retains a negative region of waste material until the retained negative region of waste material is removed from the barb element.
An eight feature is the use of a continuous roll of carrier substrate having thereon a continuous layer of fabrication material, and a formation station where successive, individual fabrication layers are formed on the carrier substrate by dividing successive segments of the continuous layer of fabrication material into a negative region of waste material and a positive region corresponding to the configuration of one individual layer. There is a stacking station where the positive regions of the successive segments of the continuous fabrication layer are sequentially stacked to form the object, and a conveyor conveys the successive segments formed at the formation station to said stacking station on the continuous carrier substrate. An affixing and separating mechanism affixes said positive region to a stack of layers at the stacking station and separates the positive region of each successive segment from the carrier substrate. A portion of the continuous carrier substrate between the formation station and said stacking station is maintained by said conveyor in a slack state.
A ninth feature is that the affixing and separating mechanism includes a platen device about which the sheet material is wrapped. The platen device is moved along a path adjacent the stack, bearing against the stack to deposit the fabrication material onto the stack. The platen device as it moves along the path retains on the platen device the substrate.
The tenth feature is employing a flexible sheet member comprising a substrate and a fabrication material having an exterior surface and an internal surface carrying an adhesive which bonds the fabrication material to the substrate but allows the substrate to be removed to expose the adhesive upon separation of the substrate from the fabrication material. A cutter in advance of the stacking station partially severs the sheet member, cutting through the fabrication material but not the substrate to form on the substrate a positive region corresponding to a predetermined configuration for an individual layer of fabrication material and a negative region of waste material. An affixing and separating mechanism at said stacking station receives the sheet material from the cutter and separates each successive carrier substrate from the individual fabrication layer thereon to expose the adhesive on said internal surface of the individual fabrication layer. This affixing and separating mechanism includes a roller device about which the sheet material is wrapped. The roller device is moved along a path adjacent a previously stacked fabrication layer which has its adhesive bearing, internal surface exposed, bearing against the previously stacked fabrication layer to deposit the fabrication material carried by the roller device on said exposed, adhesive bearing, internal surface of said previously stacked fabrication layer, with the adhesive on said internal surface of said previously stacked fabrication layer bonding to said exterior surface of the individual fabrication material. The roller device as it moves along the path retains on the roller device the substrate, and any negative region adhering thereto, to expose the internal surface of the individual fabrication material being deposited so that a successive fabrication layer may be bonded thereto. The roller device is first moved in one direction to deposit the sheet material, including both the substrate and the individual fabrication layer thereon, on the previously stacked fabrication layer, and then moves in an opposite direction to separate the substrate and any negative region of waste material thereon from the deposited fabrication layer.
The eleventh feature is that the affixing and separating mechanism includes a roller device which is moved along a path adjacent the stack. The roller device bears against the sheet member so that the exterior surface of the fabrication material contacts the exposed adhesive, bonding to the stack. The roller device as it moves along said path pulls the substrate, and any negative region adhering thereto, from the individual layer to expose its internal surface so that successive fabrication layers may be bonded thereto. The roller device is moved in a sequence so that the exterior surface of the individual fabrication layer is bonded to the stack prior to separation of the substrate from said individual fabrication layer. The roller device moves first to bond selectively the individual fabrication material to the stack and moves again to pull the substrate, and any negative region adhering thereto, from said individual fabrication layer bonded to the stack. The roller device may include a set of spaced apart parallel rollers. The rollers includes a gripper mechanism which grips an edge of the sheet member and pulls the substrate, and any negative region adhering thereto, from the stack. Preferably, a waste material removing mechanism removes, at least partially, the negative region of fabrication material from the substrate prior to the affixation of the layers.
The twelfth feature is a fabrication material removal mechanism in advance of the stacking station which selectively removes substantially all of interfering negative region from the substrate prior to stacking of the individual fabrication layers. A separator separates from the fabrication layers each successive, individual carrier substrate with any remaining non-interfering negative region remaining thereon after affixation of the previous individual fabrication layer to the next successive fabrication layer. A gripper mechanism grips an edge of a substrate and pulls the substrate, and any negative region adhering thereto, from stacked layers affixed together.